Methods for the production of polyolefins with end-functionalized groups are typically multi-step processes that often create unwanted by-products and waste of reactants and energy. For reviews of methods to form end-functionalized polyolefins, see: (a) S. B. Amin and T. J. Marks Angew. Chem. Int. Ed. 2008, 47, pp. 2006-2025; (b) T. C. Chung Prog. Polym. Sci. 2002, 27, pp. 39-85; (c) R. G. Lopez, F. D'Agosto, C. Boisson Prog. Polym. Sci. 2007, 32, pp. 419-454. A process with a reduced number of steps, even one step, would be desirable.
U.S. Pat. No. 4,110,377 discloses secondary aliphatic amines alkylated with alpha-olefins, such as ethylene, propylene, hexene, and undecene. Likewise, several literature references disclose hydroaminoalkylation of olefins using various catalysts (See, J. Am. Chem. Soc. 2008, 130, pp. 14940-14941; J. Am. Chem. Soc. 2007, 129, pp. 6690-6691; Angew. Chem. Int. Ed. 2009, 48, pp. 8361-8365; Angew. Chem. Int. Ed. 2009, 48, pp. 4892-4894; Yuki Gosei Kagaku Kyokaishi (2009), 67(8), pp. 843-844; Angewandte Chemie, International Edition (2009), 48(6), pp. 1153-1156; Tetrahedron Letters (2003), 44(8), pp. 1679-1683; Synthesis (1980), (4), pp. 305-306).
None of the above references however disclose functionalization of polyolefins, particularly polyolefins having Mn's over 500 g/mol having large amounts of vinyl terminal groups.
U.S. Ser. No. 12/487,739, filed Jun. 19, 2009 discloses certain vinyl terminated polymers that are functionalized for use in lubricant applications.
U.S. Ser. No. 12/143,663, filed on Jun. 20, 2008 discloses certain vinyl terminated polymers that are functionalized in U.S. Ser. No. 12/487,739, filed Jun. 19, 2009.
U.S. Ser. No. 12/488,093, filed Jun. 19, 2009 discloses a process to functionalize propylene homo- or copolymer comprising contacting an alkene metathesis catalyst with a heteroatom containing alkene and a propylene homo- or copolymer having terminal unsaturation.
Further, synthesis of vinyl-terminated isotactic poly(propylene) has been described in Weiqing Weng, Eric J. Markel, Armenag H. Dekmezian, Macomol Rapid Commun 2000 21, pp. 1103-1107.
Thus, there is a need to develop a means to provide functionalized polyolefins (particularly end-functionalized) by efficient reactions, particularly reactions with good conversion, preferably under mild reaction conditions with a minimal number of steps, preferably one or two steps. The instant invention's use of transition metal amide catalysts to introduce amine groups is both a commercially economical and an “atom-economical” route to end-functionalized polyolefins.
End-functionalized polyolefins that feature a chemically reactive or polar end group are of interest for use in a broad range of applications as compatibilizers, tie-layer modifiers, surfactants, adhesives, and surface modifiers. Herein is described a novel method for their production by the reaction of vinyl-terminated polyolefins with alkyl amines in the presence of a transition metal amide catalyst. This method is useful for a range of vinyl terminated polyolefins, including isotactic polypropylene (iPP), atactic polypropylene (aPP), ethylene propylene copolymer (EP), polyethylene (PE), and particularly propylene copolymers with larger alpha-olefin comonomers such as butene, hexene octene, etc. The vinyl terminated polyolefin useful herein can be linear or branched.